A front structure of a vehicle includes a bumper assembly that is supported by a frame of the vehicle. The bumper assembly includes a bumper beam coupled to the frame of the vehicle and a fascia mounted to the bumper beam to provide an aesthetic show surface.
Bumper assemblies are designed to satisfy regulatory requirements and public domain testing involving front end impacts. As one example, vehicles are subjected to testing by the Insurance Institute for Highway Safety (IIHS) and bumper assemblies are, in part, designed to satisfy such testing. Regulatory requirements and public domain testing account for not only the safety of occupants inside the vehicle, such as during vehicle-to-vehicle impacts, but also account for pedestrians outside of the vehicle. These various tests can create conflicting requirements that complicate the design of the front structure.
One testing metric, for example, is directed toward the ability of the vehicle to remain undamaged during low speed impacts and is tested by the Low Speed Damageability (LSD) test. In the LSD test, the vehicle must withstand an impact with an object of a particular size at low speeds, e.g., 15 kilometers/hour, without any visible damage to the vehicle, including the front bumper.
Other testing and requirements are directed toward protecting pedestrians. For example, testing in various countries requires that the front bumper be designed to reduce the likelihood of injury to the pedestrian during an impact of up to 50 kilometers/hour.
In order to accommodate the LSD test, bumper assemblies may be designed to be stiff to prevent damage to the exterior of the bumper assembly during a low speed impact. For example, an energy absorbing beam may be added to the bumper assembly inside the fascia to absorb energy during low speed impacts. On the other hand, bumper assemblies may be designed to be flexible to reduce the likelihood of injury to a pedestrian during impact with the pedestrian. As such, it is clear that these two tests impose conflicting demands on the design of bumper assemblies, i.e., one favoring a stiff bumper assembly and one favoring a soft bumper assembly, and complicate the design of the bumper assembly in order to accommodate both tests. Accordingly, there remains an opportunity to design a bumper assembly that addresses both of these tests.